<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    /*function add(a, b) {
        return a + b;
    }

    var result = add(1, 2);
    alert(result);*/

    var add = function (a, b) {
        return a + b;
    };
    var result = add(1, 2);
    var result1 = add(1, 2,3);
    alert(result1);
</script>
</body>
</html>